Effect of quantum fluctuations on the dipolar motion of BoseEinstein condensates in optica.pdf

Effect of quantum fluctuations on the dipolar motion of Bose-Einstein condensates in optical lattices Anatoli Polkovnikov and Daw-Wei Wang Physics Department, Harvard University, Cambridge, MA 02138 (Dated: February 2, 2008) We revisit dipolar motion of condensate atoms in one-dimensional optical lattices and harmonic 4 magnetic traps including quantum fluctuations within the truncated Wigner approximation. In 0 the strong tunneling limit we reproduce the meanfield results with a sharp dynamical transition 0 at the critical displacement. When the tunneling is reduced, on the contrary, strong quantum 2 fluctuations lead to finite damping of condensate oscillations even at infinitesimal displacement. We l argue that there is a smooth crossover between the chaotic classical transition at finite displacement u and the superfluid-to-insulator phase transition at zero displacement. We further analyze the time J dependence of the density fluctuations and of the coherence of the condensate and find several 0 nontrivial dynamical effects, which can be observed in the present experimental conditions. 3 ] The study of Bose-Einstein condensates of ultracold neling is weak the quantum fluctuations strongly modify t 1 the dynamics of the condensate in the following ways: (i) f atoms has been growing rapidly in recent years . Load- o i